Method of producing surfaceroughened metal strips



March 26, 1963 M. o. HOLOWATY 3,

METHOD OF PRODUCING SURFACE-ROUGHENED METAL STRIPS Filed D60. 1, 1959 United States Patent 3,082,517 METHQD @F PRODUCING SURFACE- ROUGEENED METAL STRIPS Michael 0. Holowaty, Gary, Ind, assignor to Inland Steel Company, Chicago, 111., a corporation of Delaware Filed Dec. 1, 1959, Ser. No. 856,411 7 Ciaims. (Cl. 29-424) This invention relates to a novel method of producing surface-roughened metal sheets or strips. The purpose of the invention is to surface-roughen a metal sheet or strip preparatory to its use in subsequent painting, enameling, varnishing and other similar surface treatments.

A long known method for producing surface-roughened metal sheets or strips has been that of sandblasting the surface in order to produce adherence of any paint, enamel or varnish or other similar application which might be used as a finish or coating thereon. This method has been far from completely satisfactory, primarily because sand particles tend to remain embedded in the sotreated surface thereby creating an uneven finish upon the application of paint, enamel or varnish thereon. Sandblasting has also been unsatisfactory due to the cost of the method and the always present hazard of the workers in the art contracting silicosis from exposure to dustcontaminated air in the region of the processing operation.

Several other methods of producing surface-roughened metal sheets or strips have been tried, but for various reasons these have proven unsatisfactory and too costly.

By the present invention surface-roughened sheets or strips are produced on a novel apparatus at less cost than has heretofore been possible. In practicing this invention the steps of spreading an adhesive compound on the surface of the metal sheet or strip, covering the adhesive coated surface with abrasive particles, applying pressure to the so-coated strip or sheet for the purpose of embedding the abrasive particles into the strip or sheet and the removal of the abrasive particles therefrom leaving the roughened surface on the sheet or strip can be accomplished at relatively low cost with increased effectiveness in the adherence characteristics of the surface.

The surface-roughened sheets are produced according to one method of practicing the invention by the use of apparatus which is comprised of a frame through which runs a conveyor upon which the sheets are conveyed to a hopper adapted to feed the abrasive particles or grit onto the upper surface of a metal sheet or strip, the particles or grit are then covered by a second metal sheet and the two sheets with the abrasive particles or grit therebetween are conveyed through pressure rolls where they are subjected to pressure which embeds the particles or grit into the surface of the two metal sheets at desired depths, these depths being controlled by the adjustable means located on each set of rolls to control the opening between each set of rolls. This method of embedding the particles into the surface of the metal sheets protects the pressure means from the abrasive particles, because the pressure means and the particles are never in direct contact with each other. After having embedded the particles into the surface of the metal, the sheets are separated and the particles or grit removed from the surface of each sheet by rotary brushes in conjunction with a liquid bath from sprinklers which are attached to the frame. The roughened sheets are then coiled on reels in which form they are used in the trade where any desired length can be readily cut from the coiled product.

From the foregoing it is apparent that this invention provides to the trade a surface-roughened metal sheet or strip to which paint, enamel, varnish and similar materials may be applied and to which said materials will more ice lastingly adhere because of the sharp surface characteristics produced by the novel method and apparatus.

The method by which the surface-roughened metal sheet or strip is produced is one which permits the ready removal of the material used to surface-roughen the sheet or strip. The method employed produces a surfaceroughened metal sheet or strip in a more economical manner than heretofore possible and one which will stand the test of hard use.

In the accompanying drawing:

FIG. 1 shows in side elevation one form of apparatus for practicing the invention;

FlG. 2 is an enlarged plan view of a portion of a roughened metal sheet or strip emphasizing in particular the indentations therein; and

FIG. 3 is a sectional view through a processed roughened metal sheet or strip showing particularly its surface characteristics and formation.

For the purpose of illustrating apparatus for practicing the method here claimed reference may be made to the accompanying drawing showing apparatus which is particularly suitable. First making reference to FIG. 1, a base metal strip 10, such as steel is fed over a conveyor device of which rolls 11 are shown carrying the metal sheet or strip. The abrasive particles 12 shown being fed onto the metal strip 10 are contained in hopper 13 which is adapted for feeding said abrasive particles. The abrasive particles or materials being finely divided and thus capable of being fed through the hopper. After the base metal sheet or strip has been coated with the abrasive particles 12, a second sheet or strip 14 is uncoiled from coiling reel 15 upon the abrasive particles 1-2 so that said particles are sandwiched betwmn the two sheets or strips 10 and 14, respectively. Both sheets or strips are then further conveyed through the set of pressure rolls 16 and 17, said pressure rolls being driven or rotated through the gear chain 18, 1 9, 20 and 21 by power means 22 for driving the metal strips through the apparatus. Other driving linkages such as belts, chains or the like may be used instead ofthe gear chain shown for purposes of rotating the pressure rolls. The upper pressure roll 17 is spring biased by spring 23 though adjustable means 24 so that the opening between rolls 16 and 17 is adjusted preferably to an opening which permits the particles 12 to be partially embedded in the surfaces of the two sheets 10 and 14. The sheets or strips are then conveyed through a second set of pressure rolls 26 and 27 which are geared through the gear chain 28, 29, 20 and 21 to the power means 22 for driving or rotating the second set of pressure rolls. The pressure roll 26 is spring biased by spring 30, the tension of which can be adjusted by the adjusting means 31. The opening between pressure rolls 26 and 27 is set so as to further embed the abrasive particles in the surface of the sheets or strips for the purpose of setting them more firmly into the surface thereof so as to produce sharper characteristics on the indentations left in the surface but the particles should not be completely embedded into the surfaces to permit removal of the same. The sheets with the abrasive particles 12 embedded into the surface thereof are then conveyed through the apparatus to apoint where they are separated by rolls 32 and '33 so as to expose the abrasive particles in a manner to permit their removal from the surfaces of the sheets by the rotary brushes 34 and 35 and Washed free by the sprinkers 36 and 37 operating in conjunction with the said rotary brushes.

The now surface-roughened metal sheets or strips are coiled onto coiling reels 38 and 39, respectively, which permits the ready handling of the Surface-roughened sheets for the purpose of sale and use in the trade. Having the sheets or strips in coil form permits the cutting thereof into desired lengths so that the user need stock only one coil instead of several sheets or strips which have been pre-cut.

The abrasive particles upon being freed from the surface of the sheets or strips .are collected in a trough 4d, partly shown, from where they are regenerated by concentration drying or the like and reclaimed for further use in the process. The selection of the abrasive particles 12 as to composition, particle size and shape is based upon the requirements imposed by the application of the sheet or strip after being surface-roughened and by the grade and type of metal used as the sheet or strip. The uniformity of feeding the abrasive particles 12 upon the lower sheet or strip is one that is easily effected by a primary coating of the strip 10 with a material having adhesive characteristics upon which the abrasive particles 12 are deposited. The abrasive particles 12 may either be applied uniformly or selectively according to a preferred design if such a design is sought to be impressed into the surface of metal sheets or strips.

In FIGS. 2 and 3 are shown views of the surfaceroughened metal sheets 10 and 14 formed by practicing the described method with the indentations therein clearly shown. These indentations being irregular in shape and having sharp surfaces produce a surface-roughened metal sheet or strip to which paint, enamel, varnish or other material to be applied thereto will more readily adhere.

While the above described method may be conveniently practiced by the apparatus shown and described it will be apparent that the invention may be practiced by the use of other related apparatus, as a result of which all modifications which fall within the scope of the following claims will be understood to have been intended.

What is claimed is:

l. A method for producing a surface-roughened metal sheet comprising the steps of: covering the surface of a metal sheet with abrasive particles, applying pressure to the abrasive particles through an intermediate surface to embed them into the covered surface of the metal sheet and subsequently removing the abrasive particles from the covered surface of the metal sheet leaving a roughened surface thereon.

2. A method of producing a roughened metal sheet comprising the steps of: spreading an adhesive compound onto the surface of a metal sheet, covering the adhesive coated surface with abrasive particles, applying pressure to the abrasive particles through an intermediate surface to embed them into the surface of the metal sheet and removing the abrasive particles from the covered surface of the sheet leaving a roughened surface thereon.

3. A method of producing a surface-roughened metal sheet comprising the steps of: spreading an adhesive compound onto the surface of the metal sheet, covering said adhesive coated sheet with abrasive particles, applying pressure through an intermediate member to the abrasive particles to embed them into the surface of the metal sheet, brushing the abrasive particles from the surface of the metal sheet, and washing the metal sheet to further cleanse the surface thereof leaving a roughened surface thereon.

4. A method of producing surface-roughened metal sheets comprising the steps of: coating a surface of a first sheet with abrasive particles, covering the abrasive coated surface of said first sheet with a second sheet of metal, applying pressure to the sheets with the abrasive particles sandwiched therebetween for embedding the abrasive particles into the surface of each sheet, separating the sheets and removing the abrasive particles from the surface of each sheet leaving roughened surfaces thereon.

5. A method of producing surface-roughened metal sheets comprising the steps of: spreading an adhesive compound onto the surface of a first sheet of metal, coating the adhesive containing surface of said first sheet of metal with abrasive particles, covering the abrasive coated surface of said first sheet with a second metal sheet, applying pressure to the sheets with the abrasive particles sandwiched therebetween for embedding the abrasive particles into the surface of the metal sheets, separating the sheets and removing the abrasive particles from the surface of each sheet leaving roughened surfaces thereon.

6. A method of producing surface-roughened metal sheets comprising the steps of: spreading an adhesive compound onto the surface of a first sheet of metal, coating the adhesive containing surface with abrasive particles, covering the abrasive coated surface of the first sheet of metal with a second sheet of metal thereby sandwiching the abrasive particles therebetween, applying pressure to the" sheets with the abrasive particles sandwiched therebetween for embedding the abrasive particles into the surface of the metal sheets, separating the sheets and brushing and washing the abrasive particles from the surface of each of said sheets leaving a roughened surface thereon.

7. A method of producing surface-roughened metal sheets comprising the steps of: spreading an adhesive compound onto the surface of a first sheet of metal, coating the adhesive covered surface of said first sheet of metal with abrasive particles, covering the abrasive coated surface of said first sheet of metal with a second sheet of metal, applying pressure to the sheets with the abrasive particles sandwiched therebetween for embedding the abrasive particles into the surface of each sheet, separating the metal sheets, brushing and washing the abrasive particles from the surface of each sheet and coiling the surface-roughened sheets onto coiling reels.

References Cited in the file of this patent UNITED STATES PATENTS 264,174 Lenox Sept. 12, 1882 2,020,177 Grove Nov. 5, 1935 2,036,615 Wean Apr. 7, 1936 2,180,078 Wilkie Nov. 14, 1939 2,528,540 Oldofredi Nov. 7, 1950 2,765,682 Wiley Oct. 9, 1956 

1. A METHOD FOR PRODUCING A SURFACE-ROUGHENED METAL SHEET COMPRISING THE STEPS OF: COVERING THE SURFACE OF A METAL SHEET WITH ABRASIVE PARTICLES, APPLYING PRESSURE TO THE ABRASIVE PARTICLES THROUGH AN INTERMEDIATE SURFACE TO EMBED THEM INTO THE COVERED SURFACE OF THE METAL SHEET AND SUBSEQUENTLY REMOVING THE ABRASIVE PARTICLES FROM THE COVERED SURFACE OF THE METAL SHEET LEAVING A ROUGHENED SURFACE THEREON. 